Open Source Software Development

We do a lot of development with Open Source stacks - especially LAMP and MEAN.
Wikipedia describes it nicely - Open-source software development, LAMP and MEAN. Follows are excerpts from Wikipedia.

LAMP

LAMP is an archetypal model of web service stacks, named as an acronym of the names of its original four open-source components: the Linux operating system, the Apache HTTP Server, the MySQL relational database management system (RDBMS), and the PHP programming language.

Linux

Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution.

Among other flavours, we have deep expertise on AWS cloud platform Linux offerings.

Apache
The role of LAMP's web server has been traditionally supplied by Apache.
The Apache HTTP Server has been the most popular web server on the public Internet.
In June 2014, Apache was estimated to serve 52.27% of all active websites.
Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation. Released under the Apache License, Apache is open-source software. A wide variety of features are supported, and many of them are implemented as compiled modules which extend the core functionality of Apache. These can range from server-side programming language support to authentication schemes.

MySQL
MySQL's original role as the LAMP's relational database management system (RDBMS) has since been alternately provisioned by other RDBMSs such as PostgreSQL, or even NoSQL databases such as MongoDB.
MySQL is a multithreaded, multi-user, SQL database management system (DBMS),[7] acquired by Sun Microsystems in 2008, which was then acquired by Oracle Corporation in 2010.[8][9] Since its early years, the MySQL team has made its source code available under the terms of the GNU General Public License, as well as under a variety of proprietary agreements.
MongoDB is a widely used open-source NoSQL database that eschews the traditional table-based relational database structure in favor of JSON-like documents with dynamic schemas (calling the format BSON), making the integration of data in certain types of applications easier and faster.

PHP
PHP is a server-side scripting language designed for web development but also used as a general-purpose programming language. PHP code is interpreted by a web server via a PHP processor module, which generates the resulting web page. PHP commands can optionally be embedded directly into an HTML source document rather than calling an external file to process data. It has also evolved to include a command-line interface capability and can be used in standalone graphical applications.[10]
PHP is free software released under the terms of PHP License, which is incompatible with the GNU General Public License (GPL) due to the restrictions PHP License places on the usage of the term PHP.[11]
PHP's role as the LAMP's application programming language has also been performed by other languages such as Perl and Python.

MEAN

MEAN is a free and open-source JavaScript software stack for building dynamic web sites and web applications.

The MEAN stack is MongoDB, Express.js, Angular, and Node.js. Because all components of the MEAN stack support programs written in JavaScript, MEAN applications can be written in one language for both server-side and client-side execution environments.

MongoDB
MongoDB (from humongous) is a free and open-source cross-platform document-oriented database program. Classified as a NoSQL database program, MongoDB uses JSON-like documents with schemas. MongoDB is developed by MongoDB Inc. and is free and open-source, published under a combination of the GNU Affero General Public License and the Apache License.
MongoDB has features of Ad hoc queries, Indexing Replication, Load balancing, File storage, Aggregation, Server side JS aggregation & capped collections.

Express.js
Express.js, or simply Express, is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs. It is the de facto standard server framework for Node.js.

AngularJS
AngularJS is a complete JavaScript-based open-source front-end web application framework mainly maintained by Google and by a community of individuals and corporations to address many of the challenges encountered in developing single-page applications. It aims to simplify both the development and the testing of such applications by providing a framework for client-side model–view–controller (MVC) and model–view–viewmodel (MVVM) architectures, along with components commonly used in rich Internet applications.

Node.js
Node.js is an open-source, cross-platform JavaScript runtime environment for developing a diverse variety of tools and applications. Although Node.js is not a JavaScript framework, many of its basic modules are written in JavaScript, and developers can write new modules in JavaScript. The runtime environment interprets JavaScript using Google's V8 JavaScript engine.
Node.js has an event-driven architecture capable of asynchronous I/O. These design choices aim to optimize throughput and scalability in Web applications with many input/output operations, as well as for real-time Web applications (e.g., real-time communication programs and browser games).
The Node.js distributed development project, governed by the Node.js Foundation, is facilitated by the Linux Foundation's Collaborative Projects program.